The big money has moved from developing psychiatric drugs to manipulating our brain networks

The psychiatric drug age may have reached its peak. Although mind-altering medications are being prescribed in record numbers, signs of a radically new approach to understanding and treating mental illness are emerging from the deep waters of neuroscience. No longer focused on developing pills, a huge research effort is now devoted to altering the function of specific neural circuits by physical intervention in the brain. [snip]

This is largely because [psychotropic] drugs tend not to be very specific in their effects on the brain. [snip]

In its place is a science focused on understanding the brain as a series of networks, each of which supports a different aspect of our experience and behaviour. By this analysis, the brain is a bit like a city: you can't make sense of the bigger picture without knowing how everything interacts. Relatively few residents of Belfast who live in the Shankill spend their money in the Falls Road and this tells us much more about the city – as these are the key loyalist and republican areas – than knowing that the average income of each area is much the same. Similarly, knowing that key brain areas interact differently when someone gets depressed tells us something important that a measure of average brain activity would miss.

The idea is that we can better understand complex human emotion and behaviour by understanding neural networks. This is where a new wave of interest is beginning to rise within neuroscience. The surge of interest is not with the concepts, which, if truth be told, became common currency in the mid-20th century, but in the extent to which research and treatment are being driven by a desire to identify and modify key brain circuits. [stop]

Can we talk about how humans aren't adapted to the 21st century?
The big one is obesity. We evolved to put on fat wherever necessary, and that was a good thing in human history. Most people until recently had to work hard and they lived just at the margin of energy balance, and a little bit more energy stored in fat meant that you could have more babies, and your babies were more likely to survive. That was pretty powerful stuff, right? Now we're in this bizarre situation that for the first time in billions of years of evolution we have an organism that is not energy limited any more.

I'm sure there are just as many articles in the UK as they are in the US about how difficult it is for people who are overweight to lose weight. Dieting really is a disaster for everybody, it takes superhuman effort to lose weight, it can be done but it isn't easy. And that's because we're evolved not only to gain weight but to hold onto it. So if that overweight person starts dieting that's just as hard as if an underweight person starts dieting, you go into a negative energy balance and all kinds of mechanisms kick in that cause us to become less active, to reshuffle energy around our bodies to defeat that effort to lose weight. So of course obesity is our number one problem.

Daniel Lieberman is a professor of human evolutionary biology at Harvard and has published numerous studies about why the human body looks and behaves the way it does. His new book is Story of the Human Body: Evolution, Health and Disease. One of his current areas of study is the advantages of barefoot running.[Snip]

What would be the three main ideas you'd hope people would take away from your book?

First, our bodies are really a hodge-podge of adaptation that accrued over a very long and complex history, that didn't evolve only to make us healthy but evolved to make our ancestors have lots of offspring. As a result, our bodies don't do the right things in the environment we live in today.

Point number two is related: the body has evolved but also cultural evolution and natural selection is overwhelming, and the result is a mismatch, we get all kinds of new diseases that we didn't used to get.

The third one?
The final point is that our instinct when we are sick is to try to treat each other – which is right and proper. But when we have a mismatch disease caused by this poor fit between our bodies and our environments we treat the symptoms only. On the one hand people are living longer and are healthier than probably ever in human history, but also suffering in new ways that are draining the economy. The US is the worst example but the UK isn't far behind, in terms of how much you are spending in treating chronic non-infectious diseases that are preventable. We can prevent heart disease, we can prevent flat feet and myopia, but we can only do so if we consider our evolution.

Can we talk about how humans aren't adapted to the 21st century?
The big one is obesity. We evolved to put on fat wherever necessary, and that was a good thing in human history. [snip] Dieting really is a disaster for everybody, it takes superhuman effort to lose weight, it can be done but it isn't easy. And that's because we're evolved not only to gain weight but to hold onto it. So if that overweight person starts dieting that's just as hard as if an underweight person starts dieting, you go into a negative energy balance and all kinds of mechanisms kick in that cause us to become less active, to reshuffle energy around our bodies to defeat that effort to lose weight. So of course obesity is our number one problem.[Stop]